Re: [PATCH 1/3] usb: musb: da8xx: Call earlier clk_prepare_enable()

From: David Lechner
Date: Tue Oct 25 2016 - 15:09:35 EST


On 10/25/2016 08:52 AM, Alexandre Bailon wrote:
The first attempt to read a register may fail because the clock may not
be enabled, and then the probe of musb driver will fail.
Call clk_prepare_enable() before the first register read.

Signed-off-by: Alexandre Bailon <abailon@xxxxxxxxxxxx>
---
drivers/usb/musb/da8xx.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/musb/da8xx.c b/drivers/usb/musb/da8xx.c
index 210b7e4..ec93602 100644
--- a/drivers/usb/musb/da8xx.c
+++ b/drivers/usb/musb/da8xx.c
@@ -366,6 +366,12 @@ static int da8xx_musb_init(struct musb *musb)

musb->mregs += DA8XX_MENTOR_CORE_OFFSET;

+ ret = clk_prepare_enable(glue->clk);
+ if (ret) {
+ dev_err(glue->dev, "failed to enable clock\n");
+ goto fail;

You can simply return ret; here instead of goto fail;

+ }
+
/* Returns zero if e.g. not clocked */
rev = musb_readl(reg_base, DA8XX_USB_REVISION_REG);
if (!rev)
@@ -377,12 +383,6 @@ static int da8xx_musb_init(struct musb *musb)
goto fail;

The unwinding on error needs to be updated so that clk_disable_unprepare() is called at this point and subsequently. Currently, all goto fail; will return without disabling the clock.

}

- ret = clk_prepare_enable(glue->clk);
- if (ret) {
- dev_err(glue->dev, "failed to enable clock\n");
- goto fail;
- }
-
setup_timer(&otg_workaround, otg_timer, (unsigned long)musb);

/* Reset the controller */